Acute Diffusion-weighted Imaging Research Articles

Acute DWI volume is a strong imaging predictor of favorable outcomes in patients with acute stroke and treated with mechanical thrombectomy

BackgroundInfarct volume on diffusion-weighted imaging (DWI) is a promising imaging marker for clinical outcomes in patients with acute stroke treated with mechanical thrombectomy (MT), but its predictive value has not been well evaluated, especially in consecutive patients. The present study aimed to elucidate the relationship between infarct volume and its change and favorable functional outcomes in consecutive patients with acute stroke who underwent MT. MethodOf patients with consecutive acute stroke who underwent MT from September 2014 through December 2019, those who were pre-morbidly independent were enrolled. Infarct volume on DWI was measured at admission (DWIinitial) and 24 h after admission (DWI24h) with semi-automated imaging software. Infarct growth (IG) was calculated as the difference between DWI24h and DWIinitial. Factors associated with a favorable outcome (mRS score 0–2) 3 months after stroke onset were assessed by multivariable analyses. Model performance was evaluated with the C-statistic. ResultsA total of 251 patients (165 male [66 %], median age 75 [IQR 67–81] years, median NIHSS score 15 [7–21]) were enrolled in the present study. Multivariable logistic regression analysis showed that DWI24h (OR 0.74, 95 % CI 0.62–0.87 for every 10-mL increment) and IG (0.74, 0.62–0.88 for every 10-mL increment) were independently and negatively associated with a favorable outcome. These associations were observed in patients with diverse vessel occlusions. Adding DWI24h or IG to the conventional predictors of favorable outcomes improved predictive accuracy (p < 0.05). ConclusionDWI infarct volume 24 h after admission and IG can be strong imaging predictors of favorable outcomes after MT.

Reversible Cytotoxic Edema in Patients with COVID-19 Associated Encephalitis Presenting Status Epilepticus

Coronavirus disease 2019 (COVID-19) is a serious infectious disease with multisystem alteration including neurological complications. COVID-19 associated encephalitis is a potentially fatal viral infection of the brain. Diffusion-weighted images (DWI) are a useful evaluation modality of cytotoxic edema in patients with encephalitis. We report on the reversible DWI change in a patient with COVID-19 associated encephalitis, who had diffused cytotoxic edema in the affected temporal lobe and accompanied status epilepticus. Sequential imaging showed that the cytotoxic edema in DWI confirmed recovery to normal after 12 days in the presence of cortical edema in fluid-attenuated inversion recovery image after aggressive neurocritical management. Thus, prompt, proper management is indispensable during the acute period and DWI may be a valuable tool for reflecting the clinical course of COVID-19 associated encephalitis.

Disconnection-Based Prediction of Poststroke Dysphagia.

Dysphagia is a common deficit after a stroke and is associated with serious complications. It is not yet fully clear which brain regions are directly related to swallowing. Previous lesion symptom mapping studies may have overlooked structural disconnections that could be responsible for poststroke dysphagia. Here, we aimed to predict and explain the relationship between poststroke dysphagia and the topologic distribution of structural disconnection via a multivariate predictive framework. We enrolled first-ever ischemic stroke patients classified as full per-oral nutrition (71 patients) and nonoral nutrition necessary (43 patients). After propensity score matching, 43 patients for each group were enrolled (full per-oral nutrition group with 17 women, 68 ± 15 years; nonoral nutrition necessary group with 13 women, 75 ± 11 years). The structural disconnectome was estimated by using the lesion segmented from acute phase diffusion-weighted images. The prediction of poststroke dysphagia by using the structural disconnectome and demographics was performed in a leave-one-out manner. Using both direct and indirect disconnection matrices of the motor network, the disconnectome-based prediction model could predict poststroke dysphagia above the level of chance (accuracy = 68.6%, permutation P = .001). When combined with demographic data, the classification accuracy reached 72.1%. The edges connecting the right insula and left motor strip were the most informative in prediction. Poststroke dysphagia could be predicted by using the structural disconnectome derived from acute phase diffusion-weighted images. Specifically, the direct and indirect disconnection within the motor network was the most informative in predicting poststroke dysphagia.

The correlation of embolic sources with infarct pattern in patients with embolic stroke (P6-5.015)

<h3>Objective:</h3> To exclusively identify potential embolic sources (PES) applying transesophageal echocardiography (TEE) and correlate them with topographic diffusion-weighted imaging patterns (DWI) in patients with embolic stroke. <h3>Background:</h3> Embolic stroke of undetermined source (ESUS) has been reported to show a relatively high stroke recurrence rate. Thus, early identification of potential embolic source (PES) is critical for acute treatment and/or secondary prevention. If acute topographic diffusion-weighted imaging patterns (DWI) would correlate with specific PES, it may prove very useful. <h3>Design/Methods:</h3> A total of 992 consecutive patients with embolic stroke were studied. Apart from the known embolic group (n=560), we focused on the unknown embolic group (n=366) that was defined as no arrhythmia during the first day from admission and no PES after general examination. DWI were classified based on the arterial supply. Age and sex adjusted odds ratio (OR) of each DWI for the different PESs were calculated. Middle cerebral arteries (MCA) were divided into 4 segments, i.e., M1~M4. Moreover, M2 segments were subdivided into superior and inferior branches. <h3>Results:</h3> 366 patients consisted of 168 with paroxysmal atrial fibrillation (pAf), 82 with paradoxical embolism (PxE), 71 with aorto-embolism (AoE), leaving 39 patients undetermined. The DWIs of internal carotid artery (OR: 15.0, p=0.0027), M1 (4.2, p=0.0003), inferior M2 (3.6, p=0.04) and multiple cortical branches (MCB) (21.6, p&lt;0.0001) were significantly associated with pAf. Striatocapsular infarction (SCI) (15.1, p&lt;0.0001) was significantly associated with PxE and multiple small scattered infarcts (8.6, p&lt;0.0001) with AoE. <h3>Conclusions:</h3> The correlations of DWI with different PESs have their distinctive characteristics. The DWI of inferior M2 as well as large infarcts and multiple cortical infarcts were associated with pAf, that of SCI with PxE and MSS with AoE. The characteristic histopathology and hydrodynamic mechanism of thrombi may determine DWI. <b>Disclosure:</b> Yasumasa Yamamoto has nothing to disclose.

Predictors of Early Neurological Improvement and Its Relationship to Thrombolysis Treatment and Long-Term Outcome in the WAKE-UP Study

Introduction: The aims of this study were to evaluate the relationship of clinical and imaging baseline factors and treatment on the occurrence of early neurological improvement (ENI) in the WAKE-UP trial of MRI-guided intravenous thrombolysis in unknown onset stroke and to examine the association of ENI with long-term favorable outcome in patients treated with intravenous thrombolysis. Methods: We analyzed data from all patients with at least moderate stroke severity, reflected by an initial National Institutes of Health Stroke Scale (NIHSS) score ≥4 randomized in the WAKE-UP trial. ENI was defined as a decrease in NIHSS of ≥8 or a decline to zero or 1 at 24 h after initial presentation to the hospital. Favorable outcome was defined as a modified Rankin Scale score of 0–1 at 90 days. We performed group comparison and multivariable analysis of baseline factors associated with ENI and performed mediation analysis to evaluate the effect of ENI on the relationship between intravenous thrombolysis and favorable outcome. Results: ENI occurred in 93 out of 384 patients (24.2%) and was more likely to occur in patients who received treatment with alteplase (62.4% vs. 46.0%, p = 0.009), had smaller acute diffusion-weighted imaging lesion volume (5.51 mL vs. 10.9 mL, p ≤ 0.001), and less often large-vessel occlusion on initial MRI (7/93 [12.1%] versus 40/291 [29.9%], p = 0.014). In multivariable analysis, treatment with alteplase (OR 1.97, 95% confidence interval [CI] 0.954–1.100), lower baseline stroke volume (OR 0.965, 95% CI: 0.932–0.994), and shorter time from symptom recognition to treatment (OR 0.994, 95% CI: 0.989–0.999) were independently associated with ENI. Patients with ENI had higher rates of favorable outcome at 90-day follow-up (80.6% vs. 31.3%, p ≤ 0.001). The occurrence of ENI significantly mediated the association of treatment with a good outcome, with ENI at 24 h explaining 39.4% (12.9–96%) of the treatment effect. Conclusion: Intravenous alteplase increases the odds of ENI in patients with at least moderate stroke severity, especially when given early. In patients with large-vessel occlusion, ENI is rarely observed without thrombectomy. ENI represents a good surrogate early marker of treatment effect as more than a third of good outcome at 90 days is explained by ENI at 24 h.

Automated CT Perfusion Detection of the Acute Infarct Core in Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction: In patients with acute ischemic stroke, the location and volume of an irreversible infarct core determine prognosis and treatment. We aimed to determine if automated CT perfusion (CTP) is non-inferior to diffusion-weighted imaging (DWI) or fluid-attenuated inversion recovery (FLAIR) in predicting the acute infarct core. Methods: In this systematic review and meta-analysis, we searched MEDLINE and EMBASE from 1960 to December 2020. Five outcome measures were examined: volumetric difference, volumetric correlation, sensitivity and specificity at the patient level, Dice coefficient, and sensitivity and specificity at the voxel level. A random-effects meta-analysis was performed for volumetric difference and correlation. Results: From 3,986 studies retrieved, 48 studies met our inclusion criteria with 46 studies on anterior circulation, one study on posterior circulation, and one study on lacunar infarct strokes. In anterior circulation stroke, there were no significant mean volumetric differences between CTP and acute DWI (cerebral blood flow [CBF] 0.52 mL, 95% CI [−0.07, 1.11], I2 0.0%; relative CBF [rCBF] 3.01 mL, 95% CI [−0.46, 6.48], I2 82.6%; relative cerebral blood volume [rCBV] −12.84 mL, 95% CI [−38.56, 12.88], I2 96.2%) and between CTP and delayed DWI or FLAIR (rCBF −1.29 mL, 95% CI [−6.49, 3.92], I2 91.8%; rCBV −5.80 mL, 95% CI [−16.20, 4.60], I2 84.2%). Mean correlation between CTP and acute DWI was 0.90 (95% CI [0.80, 0.95], I2 60.0%) for rCBF and 0.84 (95% CI [0.58, 0.94], I2 93.5%) for rCBV. Mean correlation between CTP and delayed DWI or FLAIR was 0.74 (95% CI [0.57, 0.85], I2 94.6%) for rCBF and 0.90 (95% CI [0.69, 0.97], I2 93.1%) for rCBV. Sensitivity and specificity at the patient level were reported by three studies and Dice coefficient by four studies. Statistical analysis could not be performed for sensitivity and specificity at the voxel level. Limited evidence was available for posterior circulation or lacunar infarct strokes. Conclusion: Due to significant heterogeneity and insufficient high-quality studies reporting each outcome, there is insufficient evidence to reliably determine the accuracy of CTP prediction of the infarct core compared to DWI or FLAIR.

Diffusion-Weighted Imaging Hyperintensities in Acute and Subacute-Phase Intracerebral Hemorrhage

ObjectiveDiffusion-weighted imaging hyperintensities are observed in intracerebral hemorrhage patients at times and might be associated with unfavorable functional outcomes. However, the suitable time to evaluate diffusion-weighted imaging hyperintensities to influence stroke outcome remains unclear. This study investigated the associations between acute and sub-acute diffusion-weighted imaging hyperintensities and functional outcomes among patients with acute intracerebral hemorrhage. MethodsDiffusion-weighted imaging hyperintensities were evaluated within 24 h (acute phase) and at 14 ± 5 days (sub-acute phase). An unfavorable functional outcome was a score of 5–6 on the modified Rankin Scale at 3 months. ResultsAmong 268 intracerebral hemorrhage patients, diffusion-weighted imaging hyperintensities in the acute phase were observed in 32 (11.9%). Among 227 patients who underwent a second magnetic resonance imaging in the sub-acute phase, diffusion-weighted imaging hyperintensities were observed in 57 (25.1%). Multivariable analysis revealed that the baseline intracerebral hemorrhage volume, history of stroke, and severe white matter lesions were associated with sub-acute diffusion-weighted imaging hyperintensities. The patients with unfavorable outcomes (n = 37) had a higher frequency of sub-acute diffusion-weighted imaging hyperintensities than those without (n = 190) (51.4% vs. 20.0%, P < 0.001); the frequencies of acute diffusion-weighted imaging hyperintensities were not significantly different between the groups (13.5% vs. 10.0%, P = 0.559). Sub-acute diffusion-weighted imaging hyperintensities were independently associated with unfavorable outcomes after adjusting for confounding factors (Odds Ratio, 3.35, 95% CI 1.20–9.35, P = 0.021). ConclusionThe rate of sub-acute diffusion-weighted imaging hyperintensities was higher than acute diffusion-weighted imaging hyperintensities among acute intracerebral hemorrhage patients and likely to be associated with unfavorable outcomes.

Incidental DWI Lesions in Patients with Recent Small Subcortical Infarctions

ObjectivesIncidental acute ischemic lesions distinct from the primary neurological insult are identified on diffusion-weighted imaging (DWI) in a number of conditions where cerebral microvascular pathology plays a central role. Another major manifestation of cerebral small vessel disease (CSVD) is ischemic stroke named as recent small subcortical infarction (RSSI). In this study, we sought to identify the prevalence and predictors of incidental DWI lesions in patients with RSSI. Materials and MethodsWe retrospectively analyzed a consecutive series of acute ischemic stroke patients with DWI evidence of acute lesions solely localized to perforator artery territories. Images were evaluated for the presence of additional acute or subacute subcortical DWI lesions, apart from the symptomatic lesion. Clinical features including vascular risk factor burden, together with imaging markers of chronic CSVD, were compared among patients with and without incidental acute or subacute lesions. ResultsAmong 396 patients with no alternate stroke etiology additional incidental subcortical DWI bright lesions were identified in 74 (19%) cases. These lesions were primarily localized in the corona radiata, or centrum semiovale. Patients with incidental DWI lesions were more likely to have a history of hypertension, a higher white matter hyperintensities burden in the periventricular and subcortical region, higher perivascular spaces burden in the basal ganglia, multiple cerebral microbleeds, and multiple chronic lacunes. Presence of multiple chronic lacunes (OR 5.98, 95% CI 3.18-11.24) and ≥2 vascular risk factors (OR 2.03, 95% CI 1.05-3.91) stood out as features significantly associated with incidental DWI lesions in multivariate analysis. ConclusionsOur study shows that acute or subacute ischemic lesions can be incidentally detected in approximately one-fifth of patients with RSSI. This observation suggests that the course of CSVD might be more active, temporally and spatially, in a distinct subgroup of RSSI patients, specifically those with a higher chronic lacune and vascular risk factor burden.

Acute intracerebral haemorrhage and diffusion-weighted imaging lesions: A meta-analysis.

Diffusion-weighted imaging lesions in intracerebral haemorrhage are related to a higher risk of recurrent intracerebral haemorrhage, cognitive damage, and mortality. However, it has been reported that the relationship between the risk of diffusion-weighted imaging lesions and intracerebral haemorrhage subtype or the risk factors for diffusion-weighted imaging lesions is variable. This meta-analysis was performed to evaluate this relationship. A systematic literature search up-to August 2020 was performed and 12 studies included 2815 subjects at the baseline with intracerebral haemorrhage. They were reporting relationships between the diffusion-weighted imaging lesions and intracerebral haemorrhage subtype or investigated the risk factors for diffusion-weighted imaging lesions. Odds ratio (OR) with 95% confidence intervals (CIs) was calculated to evaluate the prognostic role of diffusion-weighted imaging lesions and intracerebral haemorrhage subtype and investigated the risk factors for diffusion-weighted imaging lesions using the dichotomous and continuous method with a random or fixed-effect model. Lobar intracerebral haemorrhage was not significantly related to a higher rate of diffusion-weighted imaging lesions (OR, 1.01; 95% CI, 0.75-1.36, P=.94) compared to the non-lobar intracerebral haemorrhage. Also, history of diabetes mellitus (OR, 1.15; 95% CI, 0.83-1.60, P=.39); history of smoking (OR, 0.95; 95% CI, 0.68-1.33, P=.76); history of hypercholesterolaemia (OR, 1.04; 95% CI, 0.73-1.48, P=.83) and history of ischaemic stroke (OR, 1.63; 95% CI, 0.57-4.66, P=.36) were not significantly related to higher rate of diffusion-weighted imaging lesions compared to no history of those factors. However, the history of hypertension was significantly related to a higher rate of diffusion-weighted imaging lesions (OR, 1.33; 95% CI, 1.04-1.70, P=.02) compared to no history of hypertension. Also, Subjects with diffusion-weighted imaging lesions had a greater decrease in systolic pressure in the acute phase of the intracerebral haemorrhage (OR, 10.23; 95% CI, 7.41-13.06, P<.001) compared to without diffusion-weighted imaging lesions. Based on this meta-analysis, the history of hypertension may have an independent risk relationship with a higher rate of diffusion-weighted imaging lesions. Also, subjects with diffusion-weighted imaging lesions had a greater decrease in systolic pressure in the acute phase of the intracerebral haemorrhage compared to those without diffusion-weighted imaging lesions. This relationship forces us to recommend that identification of diffusion-weighted imaging lesions might add appreciated evidence to evaluate the progression of the underlying micro-angiopathy especially in subjects with a history of hypertension. Though further studies are needed to define the mechanisms by which these lesions may lead to cognitive damage and stroke reappearance.

Discriminative Utility of Transcranial Magnetic Stimulation-Derived Markers of Cortical Excitability for Transient Ischemic Attack

Several guidelines currently recommend acute diffusion weighted imaging (DWI) for the detection of ischemia in transient ischemic attack (TIA). However, DWI hyperintensities resolve early and only 30%-50% with clinically defined TIA show acute DWI positivity. A recent meta-analysis reported an unexplained 7-fold variation in DWI positivity in TIA across studies, concluding that DWI does not provide a consistent basis for defining ischemia. Intracortical excitability, measured using transcranial magnetic stimulation (TMS), has previously been shown to be altered after TIA and associated with ABCD2 scores; however, whether altered cortical excitability is associated with clinical and DWI-based definitions of TIA remains unclear. Individuals with TIA symptoms (N = 23; mean age = 61 ± 12) were prospectively recruited and underwent DWI and paired-pulse TMS. Multivariate linear regression was used to estimate associations between TMS-derived excitability thresholds, and clinical TIA diagnosis, and imaging-based evidence of cerebral ischemia (DWI positivity). Area under the curve (AUC) analyses was used to compare the discriminability of TMS-derived thresholds and clinical TIA diagnoses. Thresholds for intracortical inhibition in the TIA-unaffected hemisphere were significantly associated with the clinical diagnosis of TIA. No associations between TMS-derived thresholds and DWI positivity were observed. TMS thresholds showed low-moderate discriminability and values differed by age (65+) and sex. In this small sample, TMS-derived markers of intracortical excitability were associated with clinical TIA diagnoses but not DWI positivity. Our results provide preliminary evidence for the potential discriminative utility of TMS for the diagnosis of TIA and highlight the need for future work in larger cohorts.

The relation between acute intracerebral hemorrhage and diffusion-weighted imaging lesions: a meta-analysis.

Diffusion-weighted imaging lesions in intracerebral hemorrhage are related to a higher risk of recurrent intracerebral hemorrhage, cognitive damage, and mortality. However, it has been reported that the relationship between the risk of diffusion-weighted imaging lesions and intracerebral hemorrhage subtype or the possible risk factors for diffusion-weighted imaging lesions is variable. This meta-analysis was performed to evaluate this relationship. A systematic literature search up-to August 2020 was performed and 12 studies included 2815 subjects at the baseline with intracerebral hemorrhage. Odds ratio (OR) or mean difference (MD) with 95% confidence intervals (CIs) was calculated to evaluate the prognostic role of diffusion-weighted imaging lesions and intracerebral hemorrhage subtype and investigated the possible risk factors for diffusion-weighted imaging lesions using the dichotomous and continuous methods with a random or fixed-effect model. Lobar intracerebral hemorrhage was not significantly related to a higher rate of diffusion-weighted imaging lesions (OR, 1.01; 95% CI, 0.75-1.36, p = 0.94) compared to the non-lobar intracerebral hemorrhage. Also, history of diabetes mellitus (OR, 1.15; 95% CI, 0.83-1.60, p = 0.39); history of smoking (OR, 0.95; 95% CI, 0.68-1.33, p = 0.76); history of hypercholesterolemia (OR, 1.04; 95% CI, 0.73-1.48, p = 0.83); and history of ischemic stroke (OR, 1.63; 95% CI, 0.57-4.66, p = 0.36) were not significantly related to higher rate of diffusion-weighted imaging lesions compared to no history of those factors. However, the history of hypertension was significantly related to a higher rate of diffusion-weighted imaging lesions (OR, 1.33; 95% CI, 1.04-1.70, p = 0.02) compared to no history of hypertension. Also, Subjects with diffusion-weighted imaging lesions had a greater decrease in systolic pressure in the acute phase of the intracerebral hemorrhage (MD, 10.23; 95% CI, 7.41-13.06, p < 0.001) compared to without diffusion-weighted imaging lesions. Based on this meta-analysis, the history of hypertension may have an independent risk relationship with a higher rate of diffusion-weighted imaging lesions. Also, subjects with diffusion-weighted imaging lesions had a greater decrease in systolic pressure in the acute phase of the intracerebral hemorrhage compared to those without diffusion-weighted imaging lesions. This relationship forces us to recommend that identification of diffusion-weighted imaging lesions might add appreciated evidence to evaluate the progression of the underlying micro-angiopathy especially in subjects with a history of hypertension. Though further studies are needed to define the mechanisms by which these lesions may lead to cognitive damage and stroke reappearance.

Effect of workflow metrics on clinical outcomes of low diffusion-weighted imaging Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) patients subjected to mechanical thrombectomy

BackgroundAlthough accumulating evidence has demonstrated the benefit of mechanical thrombectomy (MT) in patients with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS), it is still unclear how workflow metrics...

Acute insular infarction: Early outcomes of minor stroke with proximal artery occlusion

Background and purposeWe hypothesized that admission insular infarcts could be associated with early neurological deterioration (END) in acute minor stroke with large vessel occlusion.MethodsUsing acute and follow-up diffusion-weighted imaging (DWI), we assessed insular involvement including the percent insular ribbon infarction (PIRI) scores and follow-up lesion patterns in acute minor stroke (NIHSS ≤5) with MCA/ICA occlusion. Follow-up lesion patterns were classified as swelling, new lesions, or infarct growth. END was defined as any increase in the NIHSS score.ResultsAmong 166 patients (age: 66±12 y, 60.8% male), 82 (49.4%) had insular lesions on baseline DWI, and 64 (38.6%) had PIRI scores ≥2. On follow-up DWI, infarct growths, new lesions, and swelling were observed in 34.9%, 69.9%, and 29.5% of patients. Infarct growths were significantly more frequent in patients with insular infarcts (43.9%), especially those with a PIRI score of 2 (54.8%), than in patients without insular infarcts (p = 0.02). While END was not significantly different in patients with and without insular lesions, insular lesions were independently associated with infarct growths (OR 2.18, 95% CI 1.12–4.26, p = 0.02) and END due to infarct growth (OR 2.54, 95% CI 1.12–5.76, p = 0.03), particularly in those with PIRI scores ≥2.ConclusionIn acute minor stroke with MCA/ICA occlusion, insular lesions on admission DWI, especially in patients with PIRI scores ≥2, were more likely to exhibit infarct growth and END due to infarct growth. This finding may help identify patients with higher risks of clinical worsening following acute minor stroke with large vessel occlusion.

Dysphasia is associated with diffusion-weighted MRI abnormalities in patients with transient neurological symptoms

BackgroundThe clinical characteristics of diffusion-weighted imaging (DWI) abnormalities after transient neurological symptoms are of great significance for the early diagnosis and urgent intervention of transient ischemic attack (TIA). This study was aimed to investigate the clinical characteristics associated with acute DWI lesions in transient neurological symptoms.MethodsWe retrospectively recruited 302 patients with transient neurological symptoms. According to DWI findings, they were divided into DWI positive and DWI negative group. The clinical characteristics and the TIA-related scores such as ABCD2, ABCD3, ABCD3I, Dawson score, and the Diagnosis of TIA (DOT) score were compared between the two groups. Logistic regression analysis and receiver operating characteristic curves were used to identify the independent factors and compare the predictive value of different TIA scores for acute DWI lesions.ResultsA total of 302 patients were enrolled in this study. The mean age was 61.8 years, and 67.2% were male. We found 89 (29.5%) patients with DWI positivity. Logistic regression analysis showed the characteristic associated with DWI lesions was dysphasia (OR 2.226, 95% CI 1.220–4.062). The area under the curve for Dawson score and the DOT score was 0.610 (95% CI 0.543–0.678) and 0.625 (95% CI 0.559–0.691), respectively.ConclusionWe found that DWI lesions were detected in 29.5% of patients with transient neurological symptoms and were associated with dysphasia. Dawson score and DOT score could have a higher predictability of DWI lesions in patients with transient neurological symptoms.

Mapping the ischemic penumbra and predicting stroke progression in acute ischemic stroke: the overlooked role of susceptibility weighted imaging

ObjectivesAsymmetrically prominent veins (APVs) detected on susceptibility weighted imaging (SWI) in acute stroke patients are assumed to signify compromised cerebral perfusion. We aimed to explore the role of APVs in identifying the ischemic penumbra and predicting stroke progression in acute stroke patientsMethodsTwenty patients with a middle cerebral artery ischemic infarction presenting within 24 h of symptoms onset underwent SWI following our standard MR stroke protocol imaging sequences which included diffusion-weighted imaging (DWI). Follow-up (FUP) FLAIR images were obtained at least 5 days after the initial MRI study. The Alberta Stroke Program Early CT Score (ASPECTS) was used to determine the initial infarct size, extent of APVs and final infarct size on initial DWI, SWI, and FUP images respectively. For each patient, SWI was compared with DWI images to determine match/mismatch of their respective ASPECTS values and calculate mismatch scores, whereas acute DWI findings were compared with follow-up images to identify infarct growth (IG) and calculate infarction growth scores (IGS).ResultsIG occurred in 6/10 patients with a positive DWI-SWI mismatch and in none of the patients without a positive DWI-SWI mismatch. A positive DWI/SWI mismatch was significantly associated with IG (χ2 = 8.57, p = 0.0138, Cramer’s V = 0.65). A significant inverse correlation was found between SWI ASPECTS and IGS (rs = − 0.702, p = 0.001). DWI-SWI mismatch scores were strongly correlated with IGS. (rs = 0.788, p = 0.000)ConclusionA positive DWI-SWI mismatch is an indicator of the ischemic penumbra and a predictor of infarct expansion if left untreated.

Impact of stroke volume on motor outcome in neonatal arterial ischemic stroke.

Neonatal arterial ischemic stroke (NAIS) can lead to long-term neurological consequences such as cerebral palsy (CP). The aim of this study was to evaluate the predictive value of acute diffusion-weighted imaging (DWI) for CP by analyzing stroke volume next to brain structure involvement. We included 37 term-born infants with NAIS prospectively registered in a nationwide pediatric stroke registry. DWI was performed between 0 and 8 days (mean 3 days) after stroke manifestation. Participants were neurologically assessed at the age of 2 years. We calculated the stroke volume (in mm3) and the ratio of the stroke volume to the volume of the entire brain (relative stroke volume). The predictive value of the relative stroke volume was analyzed and an optimal threshold for classification of children with high- and low-rates of CP was calculated. Predictive value of brain structure involvements and the prevalence of CP in combinations of different brain structures was also assessed. Sixteen children (43.2%) developed CP. Relative stroke volume significantly predicted CP (p<.001). Its optimal threshold for division into high- and low-rate of CP was 3.3%. The basal ganglia (OR 8.3, 95% CI 1.2-60.0) and basis pontis (OR 18.5, 95% CI 1.8-194.8) were independently associated with CP. In addition to determining the involvement of affected brain areas, the volumetric quantification of stroke volume allows accurate prediction of cerebral palsy in newborns with NAIS.

What remains after transient global amnesia (TGA)? An ultra-high field 7 T magnetic resonance imaging study of the hippocampus.

The aim was to study whether ultra-high field 7 T magnetic resonance imaging (MRI) can demonstrate chronic focal defects in the hippocampus corresponding to the former acute diffusion-weighted imaging (DWI) lesions and to assess chronic T2-hyperintense hippocampal lesion load in transient global amnesia (TGA) patients. Follow-up of 7 T MRI of the hippocampus was performed in 13 patients with documented hippocampal DWI lesions (detected via 3 T MRI) after acute TGA. The location of the DWI lesions was transformed to 7 T T2 images after data co-registration. Additionally, the T2-hyperintense lesion load was estimated in each patient and compared with that of 13 healthy controls. Magnetic resonance imaging (7 T) was performed after a median of 4 months. No structural abnormality at the site of the previous TGA lesion was observed in any case. None of the controls showed DWI lesions. There was no significant difference between patients and controls concerning the number (P=0.67) or volume (P=0.45) of T2-hyperintense hippocampal lesions. Diffusion-weighted imaging lesions in patients with TGA do not provoke any visible sequelae and do not result in hippocampal cavities. The occurrence of incidental hippocampal T2 lesions after TGA is not more frequent than in controls.

Incidence and Predictors of Acute Ischemic Lesions on Brain Magnetic Resonance Imaging in Patients With a Clinical Diagnosis of Transient Ischemic Attack in China.

Background: The associations between the clinical characteristics and diffusion-weighted imaging (DWI) positivity in patients with a clinical diagnosis of transient ischemic attack (TIA) are still poorly understood. The purpose of our study was to determine the incidence of TIA related acute infarction by DWI, and to determine the underlying predictors of DWI positivity in TIA patients.Methods: Between Jan 2017 and Dec 2018, we retrospectively enrolled 430 patients with a clinical diagnosis of TIA who underwent DWI. Patients were divided into those with acute ischemic lesions (DWI positive group) and those without (DWI negative group). The clinical characteristics, laboratory data, and imaging parameters were compared between the two groups.Results: A total of 430 time-based TIA patients (mean age, 61.4 ± 13.0) were enrolled in this study. About 126 (29.3%) of TIA patients had a DWI positive lesion in our series. Comparing TIA patients with positive DWI to those with negative DWI, acute lesions were more likely to be more male, have higher hyperlipidemia and a smoking history, more speech abnormalities and increased motor weakness; and higher systolic and diastolic blood pressure, homocysteine, fasting blood glucose, and the scores of ABCD2, ABCD3, ABCD3-I, and Dawson. Several independent predictors of DWI positivity were identified with logistic regression analysis: motor weakness (odds ratio 4.861, P = 0.021), speech abnormalities (odds ratio 4.029, P = 0.024), and ABCD3-I (odds ratio 13.141, P = 0.001). ABCD3-I showed the greatest area under the ROC curve, with a sensitivity of 85.7% and specificity of 72.4%.Conclusion: In patients with a clinical diagnosis of TIA, 29.3% demonstrated acute DWI lesions on brain magnetic resonance imaging (MRI). They were associated with motor weakness, speech abnormalities and higher ABCD3-I score at admission.

Hippocampal diffusion abnormality after febrile status epilepticus is related to subsequent epilepsy.

To assess hippocampal signal changes on diffusion-weighted imaging (DWI) during the acute period after febrile status epilepticus (FSE) and to examine the relationship between DWI and subsequent epilepsy. A prospective, multicenter study of children with a first episode of FSE was performed. The patients underwent magnetic resonance imaging (MRI) within 3days of FSE, and signal intensity was evaluated on DWI. Electroencephalography studies within 3days of FSE were also assessed. Nine to 13years after FSE, information on subsequent epilepsy was obtained. Twenty-two children with FSE were evaluated. DWI showed unilateral hippocampal hyperintensity in six patients (27%). Three of six patients with hippocampal hyperintensity had ipsilateral thalamic hyperintensity. On EEG within 3days of FSE, five of six patients with hippocampal hyperintensity had ipsilateral focal slowing, spikes, or attenuation. Nine to 13years later, the outcomes could be determined in five patients with hippocampal hyperintensity and in 10 without. All 5 patients with hippocampal hyperintensity had hippocampal atrophy and developed focal epilepsy, whereas only 1 of 10 patients without hippocampal hyperintensity developed epilepsy (P=0.002). Ictal semiology was concordant with temporal lobe seizures in all patients. Ipsilateral temporal epileptiform abnormalities were seen on EEG in four of five at last follow-up. Acute DWI hippocampal hyperintensity was seen in 27% of patients with FSE. Acute DWI hyperintensity suggests cytotoxic edema caused by prolonged seizure activity. Hippocampal DWI hyperintensity is related to mesial temporal lobe epilepsy and can be a target of neuroprotective treatments to prevent the onset of epilepsy.

Diffusion Imaging of Cerebral Diaschisis in Neonatal Arterial Ischemic Stroke

BackgroundNeonatal arterial ischemic stroke is a leading cause of cerebral palsy and lifelong disability. Diffusion-weighted imaging has revolutionized diagnosis and facilitated outcome prognostication in acute neonatal arterial ischemic stroke. Diaschisis refers to changes in brain areas functionally connected but structurally remote from primary injury. We hypothesized that acute diffusion-weighted imaging can quantify cerebral diaschisis and is associated with outcome from neonatal arterial ischemic stroke. MethodsSubjects were identified from a prospective, population-based research cohort (Alberta Perinatal Stroke Project). Inclusion criteria were unilateral middle cerebral artery neonatal arterial ischemic stroke, diffusion-weighted magnetic resonance imaging within 10 days of birth, and more than 12-months follow-up (pediatric stroke outcome measure). Diaschisis was characterized and quantified using a validated software method (ImageJ). Volumetric analysis assessed atrophy of affected structures. Diaschisis scores were corrected for infarct size and compared with outcomes (Mann-Whitney). ResultsFrom 20 eligible neonatal arterial ischemic strokes, two were excluded for poor image quality. Of 18 remaining (61% male, median age 3.2 days), 16 (89%) demonstrated diaschisis. Thalamus (88%) was the most common location in addition to corpus callosum (50%). Age at imaging was not associated with diaschisis. Affected structures demonstrated atrophy on imaging. Long-term outcomes available in 81% (median age 7.5 years) were not associated with diaschisis scores. ConclusionsCerebral diaschisis occurs in neonatal arterial ischemic stroke and can be quantified with diffusion-weighted imaging. Occurrence is common and should not be mistaken for additional infarction. Determining clinical significance will require larger samples with well-characterized long-term outcomes.